Dispersal of relatively viscous liquids such as liquid soaps, hand sanitizing fluids, cosmetic creams, insect repellant lotions and similar fluids is often accomplished by either squeezing plastic tubes or bottles with closable caps or pumping fluid from bottles with reciprocating ball-valve pumps accessed by top mounted plungers. Conventional dispensers of these types dominate the marketplace for packaging dispensable viscous fluids and range in size from small pocketable packets to large jugs. Such containers are universally popular despite being well known for wasting irretrievable product, inconvenient handling, unfortunate leaks, content contamination problems and product loss through evaporation.
The art of packaging has long offered solution to some of these shortcomings. For example, Bensen U.S. Pat. No. 2,777,612 (1957) disclosed a tube dispenser with a collapsible inner product pouch associated with a pneumatic pump system to dispense most of the viscous liquid product while protecting it from atmospheric contamination. Three examples of external pumps using a reciprocating chamber are Nilsson U.S. Pat. No. 5,099,885 (1992), Thomsen U.S. Pat. No. 5,067,635 (1991), and Thomsen U.S. Pat. No. 5,207,355 (1993). Nilsson disclosed a dispensing pump with an elastic pump chamber, deformable under direct pressure, and the subsequent hydraulic pressure closing an inlet valve and opening an outlet valve. Thomsen discloses two forms of an exterior dispensing pump with elements arrayed linearly that relies on a sequencing mechanism that first closes the inlet passage from the reservoir, then builds subsequent pressure in pump chamber resulting in fluid dispensing from an exit valve. An internal pump design is disclosed by Abergel U.S. Pat. No. 6,789,706 (2004). Abergel describes a pump chamber enclosed by a reservoir wall that communicates pressure to the pump which builds fluid pressure that activates both outlet and inlet valves for discharging and refill. Brennan U.S. Pat. No. 5,810,203 (1998), Brown U.S. Pat. No. 5,431,634 (1995), and Py U.S. Pat. No. 7,322,491 (2008) all disclose various additional elements of pump closure art. A simple, low-cost pump design is described by Harper U.S. Pat. No. 7,828,176 (2010). Harper discloses a reservoir chamber and dispersal pump chamber providing fluidic access through a closable aperture in a common pump wall. Aside from Harper, none of these disclosures neither describes nor suggests a particularly low-cost, minimal part pump action that is easy to manufacture and convenient to operate. The need for a fluid dispenser that employs an internal pump in thin compact packaging of minimal construction remains open to new designs.